package com.hmdp.service.impl;

import cn.hutool.core.lang.hash.Hash;
import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.stream.Stream;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;


    public void saveShop2Redis(Long id, Long expireTime) {
        Shop shop = getById(id);
        RedisData data = new RedisData();
        data.setData(shop);
        data.setExpireTime(LocalDateTime.now().plusSeconds(expireTime));
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(data));
    }

    private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);

    public Shop queryWithLogicalExpire(Long id) {
        String s = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);

        RedisData redisData = JSONUtil.toBean(s, RedisData.class);
        Shop shop = JSONUtil.toBean((JSONObject) redisData.getData(), Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();
        if (expireTime.isAfter(LocalDateTime.now())) {
            return shop;
        }
        String lockKey = LOCK_SHOP_KEY + id;
        boolean b = tryLock(lockKey);
        if (b) {
            CACHE_REBUILD_EXECUTOR.submit(() -> {
                try {
                    this.saveShop2Redis(id, 20L);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                } finally {
                    delectLock(lockKey);
                }
            });
        }
        return shop;
    }

    @Override
    @Transactional
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null) {
            return Result.fail("店铺id不能为空");

        }
        updateById(shop);
        stringRedisTemplate.delete(CACHE_SHOP_KEY + id);
        return Result.ok();
    }

    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        if (x==null||y==null){
            Page<Shop> page = query()
                    .eq("type_id", typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            // 返回数据
            return Result.ok(page.getRecords());
        }
        int from = (current-1)*SystemConstants.MAX_PAGE_SIZE;
        int end = current*SystemConstants.MAX_PAGE_SIZE;
        String key =SHOP_GEO_KEY+typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()
                .search(key, GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeDistance().limit(end));
        if (results==null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> content = results.getContent();
        if (content.size()<from) {
            return Result.ok(Collections.emptyList());
        }
        List<Long> ids = new ArrayList<>(content.size());
        Map<String,Distance> distanceMap = new HashMap<>(content.size());
        content.stream().skip(from).forEach(result->{
            String shopIdStr = result.getContent().getName();
            ids.add(Long.valueOf(shopIdStr));
            Distance distance = result.getDistance();
            distanceMap.put(shopIdStr,distance);
        });
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD(id," + StrUtil.join(",", ids) + ")").list();
        for (Shop shop:shops){
            shop.setDistance(distanceMap.get(shop.getId().toString()).getValue());
        }
        return Result.ok(shops);
    }

    @Override
    public Result queryById(Long id) {
//        Shop shop = queryWithMutex(id);
//        封装的工具类使用互斥锁解决缓存穿透
        Shop shop = cacheClient.queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        逻辑删除解决缓存击穿
//        Shop shop = cacheClient.queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);
        if (shop == null) {



            return Result.fail("店铺不存在！");
        }
        return Result.ok(shop);
    }

    public Shop queryWithMutex(Long id) {
        String s = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
        if (StrUtil.isNotBlank(s)) {
            return JSONUtil.toBean(s, Shop.class);
        }
        if (s != null) {
            return null;
        }
        String lockKey = LOCK_SHOP_KEY + id;
        Shop shop = null;
        try {
            boolean b = tryLock(lockKey);
            if (!b) {
                Thread.sleep(50);
                return queryWithMutex(id);
            }
            log.debug("成功");
            shop = getById(id);
            Thread.sleep(200);
            if (shop == null) {
                stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
                return null;
            }
            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        } finally {
            delectLock(lockKey);
        }

        return shop;
    }

    public Shop queryWithPassThrough(Long id) {
        String s = stringRedisTemplate.opsForValue().get(CACHE_SHOP_KEY + id);
        if (StrUtil.isNotBlank(s)) {
            return JSONUtil.toBean(s, Shop.class);
        }
        if (s != null) {
            return null;
        }
        Shop shop = getById(id);
        if (shop == null) {
            stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, "", CACHE_NULL_TTL, TimeUnit.MINUTES);
            return null;
        }
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(shop), CACHE_SHOP_TTL, TimeUnit.MINUTES);
        return shop;
    }

    private boolean tryLock(String key) {
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }

    private void delectLock(String key) {
        stringRedisTemplate.delete(key);
    }
}
